Quiet Plus® VAV Terminal Units

Quiet Plus variable air volume terminal units are used in ducted air-conditioning systems to regulate the flow of air to a room or group of rooms, to maintain comfortable temperature levels, and to provide significant energy savings.

Building owners and designers are extremely concerned about the way sound affects occupant comfort and productivity. Noise attenuation is a critical component of a successful building environment and Warren's Quiet Plus variable air volume terminal units offer the quietest performance available today.

Warren Quiet Plus VAV terminal units are available as single-duct throttling units (Model ST); rectangular duct slip-in and bypass (relief); intermittent fan-powered, parallel flow terminal units (Model FBI); and constant-volume, fan-powered, series flow terminal units (Model FBC).
Models ST, FBI, and FBC Quiet Plus variable air volume terminal units are designed for use in low, medium, or high pressure systems to provide quiet operation, laminar airflow and precision control. All units include the patented Zebra® Precision Air Valve, which sets the standard of performance for air valves in the HVAC industry. A wide range of capacities and voltages are available. Quiet Plus units may be selected for heating only, cooling only, cooling with re-heat, ventilation only, or combination heating and cooling applications. Electronic, direct digital, electric, or pneumatic controls are available to provide pressure independent or pressure dependent operation as well as a wide variety of specific control sequences.

Warren's Quiet Plus terminal units are designed to produce low sound levels, eliminating the need for additional sound attenuation in most applications. All Quiet Plus units feature the Zebra® precision air valve which is inherently quieter than single or opposed blade damper configurations.

Quiet Plus

Key Benefits

  • Individual Room Temperature Control
  • Improved Health, Comfort and Productivity
  • HVAC System Design Flexibility
  • Energy Efficient


What are clients are saying

Don Wall
President, Don Wall Construction Co., General Contractors, New Haven Savings Bank. Milford, Connecticut
"Overall we have been very pleased with the performance of these VAV terminal units. I was very skeptical when we first looked at the QUIET PLUS® VAV terminal units. After all the ZEBRA® damper looked different than any other damper we had seen in a VAV box. We tested them on one floor of the New Haven Savings Bank and our clients were very impressed. Since our initial installation, they have reordered QUIET PLUS® VAV terminal units for four additional floors. The laminar air flow and direct linear stroke of the ZEBRA® air valve are a marked improvement over other VAV boxes with conventional dampers. The Warren VAV box is much more durable than the ones we used to purchase. We will use them on many more projects in the future."

Case Studies

High-tech Air Distribution Products Help Cure “Sick Building Syndrome” at Martin County Courthouse

High-tech Air Distribution Products Help Cure “Sick Building Syndrome” at Martin County Courthouse

Stuart, FL - The recent discovery of an extreme incidence of fungal growth and bacteria in Stuart's Martin County Courthouse…

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